nextjs-bundle-analysis.yml

name: Next.js Bundle Analysis

on:
  pull_request:
  push:
    branches: [main, v3, v4-v2]
  workflow_dispatch:

permissions:
  pull-requests: write
  contents: read

jobs:
  analyze:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        package: ['examples/swr-site', docs]

    steps:
      - name: Cancel Previous Runs
        uses: styfle/cancel-workflow-action@0.12.1
        with:
          access_token: ${{ github.token }}

      - name: Checkout Main
        uses: actions/checkout@v4

      - uses: pnpm/action-setup@v4

      - name: Install Node.js
        uses: actions/setup-node@v4
        with:
          node-version-file: .node-version
          cache: pnpm

      - name: Install Dependencies
        run: pnpm i

      - name: Restore Next.js Build
        uses: actions/cache@v4
        id: restore-build-cache
        env:
          cache-name: cache-next-build
        with:
          # If you use a custom build directory, replace all instances of `.next` in this file with your build directory
          # ex: if your app builds to `dist`, replace `.next` with `dist`
          path: ${{ matrix.package }}/.next/cache
          # Change this if you prefer a more strict cache
          key: ${{ runner.os }}-build-${{ env.cache-name }}

      - name: Build Next.js App
        # Change this if your site requires a custom build command
        run: cd ${{ matrix.package }} && ./node_modules/.bin/next build

      # Here's the first place where next-bundle-analysis' own script is used
      # This step pulls the raw bundle stats for the current bundle
      - name: Analyze Bundle
        run: cd ${{ matrix.package }} && npx -p nextjs-bundle-analysis report

      - name: Upload bundle
        uses: actions/upload-artifact@v4
        with:
          # Check since we can't use slashes in name
          name: bundle-${{ matrix.package == 'docs' && 'docs' || 'swr-site' }}
          path: ${{ matrix.package }}/.next/analyze/__bundle_analysis.json

      - name: Download Base Branch Bundle Stats
        uses: dawidd6/action-download-artifact@v6
        if: success() && github.event.number
        with:
          name: bundle-${{ matrix.package == 'docs' && 'docs' || 'swr-site' }}
          workflow: nextjs-bundle-analysis.yml
          branch: ${{ github.event.pull_request.base.ref }}
          path: ${{ matrix.package }}/.next/analyze/base/bundle

      # And here's the second place - this runs after we have both the current and
      # base branch bundle stats, and will compare them to determine what changed.
      # There are two configurable arguments that come from package.json:
      #
      # - budget: optional, set a budget (bytes) against which size changes are measured
      #           it's set to 350kb here by default, as informed by the following piece:
      #           https://infrequently.org/2021/03/the-performance-inequality-gap/
      #
      # - red-status-percentage: sets the percent size increase where you get a red
      #                          status indicator, defaults to 20%
      #
      # Either of these arguments can be changed or removed by editing the `nextBundleAnalysis`
      # entry in your package.json file.
      - name: Compare with Base Branch Bundle
        if: success() && github.event.number
        working-directory: ${{ matrix.package }}
        run: ls -laR .next/analyze/base && npx -p nextjs-bundle-analysis compare

      - name: Get Comment Body
        id: get-comment-body
        if: success() && github.event.number
        run: |
          echo "body<<EOF" >> $GITHUB_OUTPUT
          echo "$(cat ${{ matrix.package }}/.next/analyze/__bundle_analysis_comment.txt)" >> $GITHUB_OUTPUT
          echo EOF >> $GITHUB_OUTPUT

      - name: Add comment to PR
        uses: marocchino/sticky-pull-request-comment@v2.9.0
        if: success() && github.event.number
        with:
          header: 'bundle-analysis-${{ matrix.package }}'
          message: ${{ steps.get-comment-body.outputs.body }}